Planktonic foraminiferal δ18O,pollen, and opal records from Santa Barbara Basin are used to evaluate climatechanges in the northeast Pacific during marine isotope stages (MIS) 6 and5. While the oak and foraminifera record the major glacial-interglacial changes,opal is not correlated with these large-scale transitions. Surface water warmingin the basin was synchronous with terrestrial warming but earlier than icesheet melting and increasing Northern Hemisphere insolation at TerminationII. During and immediately after deglaciation, our marine proxies indicatethe presence of an isothermal upper water column. Later in substage 5E, thewater column became thermally stratified, surface productivity increased,and laminated sediments began accumulating. Sediment trap and hydrographicdata suggest these changes were due to the onset of a strong seasonal cyclesimilar to that seen today in the basin. A series of rapid coolings withinMIS 5 appears to be synchronous with North Atlantic ice-rafting events andGreenland stadials.